Blueback Salmon ; Sockeye Salmon 



convex behind, the preopercle very broad, with the lower limb 

 little developed; eye much smaller than in chinook of same size; 

 maxillary slender and narrow, but extending somewhat beyond 

 the eye; teeth very few and small, only 2 or 3 on the vomer, 

 those on tongue very feeble; fins small. Colour, bluish green on 

 back, the sides silvery, with dark punctulations ; no spots except 

 a few rather obscure ones on top of head, back, dorsal fin, 

 adipose fin, and the rudimentary upper rays of the caudal; pec- 

 torals dusky, and with dusky edge; sides of head without dark 

 colouration as seen in the chinook; males mostly red in fall, and 

 with the usual changes of form. 



The silver salmon is easily distinguished from the chinook, 

 which it most resembles, by its fewer scales, fewer pyloric 

 coeca, and fewer branchiostegals. 



Blueback Salmon ; Sockeye Salmon 



Oncorhynchus nerka (Walbaum) 



The blueback salmon is found from the coast of southern 

 Oregon, north to northern Alaska and Kamchatka, and Japan. 

 It has been occasionally reported from the Sacramento and Kla- 

 math rivers, but is not at all common south of the Columbia. 

 The principal rivers in the United States which it frequents are 

 the Columbia, Quinialt and Skagit, in each of which very great 

 runs occur. It enters the Fraser in enormous numbers, and is 

 the most abundant and valuable salmon in Alaska. 



The runs in the different rivers begin at different times, 

 depending partly upon the distance of the spawning beds from 

 the sea, and the temperature of the water. 



The run in the Columbia begins in March or April, and the 

 fish ascend to the headwaters of the Salmon River in Idaho, 

 which they reach in July and August, a journey of some 1,000 

 miles from the sea. In the Skagit the run begins somewhat 

 later, the fish reaching their spawning grounds in and above 

 Baker Lake in August and September. 



The run in the Fraser River is synchronous with that in the 

 Skagit, or possibly a little later. In Alaska most of the streams 

 which it enters are relatively short, and the runs do not begin 

 until a short time before the spawning period. So far as known 

 the blueback enters only such rivers as have lakes in their head- 



